Electrical regulator



March 1, 1932; F. JAHN ELECTRICAL REGULATOR Filed Oct. 24, 1950 2 Sheets-Sheet Fig. 2

Fig. I

Fig. 3

Fig. ('2

Fig. 5

Inventor 1 Fritz Jahn W M 8 His Attorney.

Filed Oct. 24, 1930 2 Sheets-Sheet 2 Fig. 8

Fig. Fig. \0

Inventor 2 Fritz Jahn,

b9 64-M IZ M His Attorneg.

Patented Mar. 1, 1932 UNITED STATES.

PATENT rarrz JAHN, or BERLIN-inflow, onammr, ASSIGNOR T GENERAL ELECTRIC 00I- PANY, a conroaa'rron or fmzw Yomr I ELECTRICAL REGULATOR Application filed October 24, 1930, Serial No.

6:- regulators are well known in the art. In the past such regulators have never'been entirelysatisfactory because the peculiar characteristics of carbon piles, which militate against their direct actuation by the ordilo nary regulator operating element which reizawhich leads tOCOlHPllCfl-tl their resistance decreases with increases in, x v g In other ,words, thepull decreases gradually sponds to the condition to be regulated,have been compensated for, if at complicated apparatus.

. The first characteristic of carbon piles ons is the fact that.

pressure applied to them. Now, as in practically all automatic regulators, an increase in the value of the regulated quantity is accom- 9Ipanied by an increase in .the force produced by the element, usually a solenoid, connected tobe responsive to the quantity, a direct application of the force to the pilev will result inadecreasein resistance; whereas, an

.5:increase in resistance is what is usually needed. Thus, itthe regulator is a voltage reguf lator, an increase in voltage should be accompanied by an increase in resistance, regard v less of whether the resistance is in the cir- 391011) wvhosc voltage is to, be regulated, or

whether it is in the field circuit of a generator. To overcome this difliculty prior carbon pile regulators have been provided with means, such as weights or springs, which normally keep the pile compressed, the actuating element being connected to decrease the pressure on the pile with increases in the value of the regulated quantity. Such additional means increases the number of moving parts of the regulator andalso increases the friction in it, withthe result that its'speed and'sensitivity of response are impaired.

The second characteristic of carbon'piles which leads to difficulties when they are used in automatic regulators, is the fact that their change of resistance isnot a simple straight line function of the compressing pressure.

In fact, their resistance-pressure characteristic resembles an hyperbola, the resistance,

5 ordinates, being a maximum at zero presall, by relatively.

490,966, and in Germany December- 27, 1929.-

used as'th'e actuating element of a carbon 5 pile regulator, is aboutas far on the other side of a'straight line ias is the pressure. resistance characteristic of a carbon pile,

Such a'pull characteristic, with pull a's ordi:

nates against displacement of thecore from i "which is What ha'siheretofore een generally theniid; position, as,abscissae,.resembles 'a 1 quarter; section of an ellipse whose center is at, '1 the on n of coordinates, and whose manor ax s is. along the l10r1zontal of coord nates,

at first, andthen more rapidly as' the Idis placement increases. The-result is that when a carbon I pile. is

of special" connecting means, "a very erratic action, which, also is accompan ed by considerable, hunting, isthe usual consequence,

because, given changesin the-energizationof Jinterposing, special mechanical connections between the solenoid coreand the pile, as tor example, special lever systems or systems utilizing the hyperbolic pressure-volume characteristic ofa gas. However, these arrangements are complicated, expensive and increase the friction in the regulator thus tending to decrease; of action. Furthermore,-most of these arrangements eem to assume that the pull characteristic of a solenoid is a straight line, In accordance withthis. invention there is provided-a novel electromagnetic operating means for carbon pile regulators,which, with a rn-inmum number of moving parts, provides an operating characteristic suitable for op eration of, a carbonpile,and which may be] directly electrically connected tothe circuit to be regulated, andwhich maybe directly mechanically connected to thecarbon' pile."

actuated by ,thefcore ofian ordmary solenoid, without the interposition v p its sensitivity and speed c An object of the invention is to provide a new and improved electrical regulator. Another object of the invention is to provide a simplified electromagnetic actuating element for electrical regulators which is particularly adapted :for use. in. carbon pile regulators, or

any regulator with a compiessible resistance trates one. arrangementof the operating; windings of the magnet \vhereby'incre'ases in the; regulated quantity j results in a decrease in the net-ampere turns of: them'agnet; Fig. 2 isa modification of the arrangement shown in 1; F 3 illustrates the operating.

characteristics of a 'carbonipile resistance;

' F illustrates pictoriallythexsignificance of the coordinates used in'Fig.":3'; Fig. 5 is a front elevation of thecore and: armature of."

the operating magnet, 6 is asideelevation thereof," Fig, 7 shows graphically the "operating characteristic of "the operating magnetyFig. 8 is a modified arrangement of;

connections of a carbon pile whereby 'anincreased? current-carrying capacity is obtain ed {Fig 9 'is' a side elevation of th'ecompleted regulator embodying.v the invention; while'Fig. 10 is a frontview thereof.

In Fig. 1,11 'is"an"electric' circuityone of whose electrical quantities, in this case voltage', isito' be regulated by'the regulator.

Across this-circuit" are' connected coils 2. and: 3, coil13hav1ng in SG'IIEStlIBI'EWitll a'constantv currentdevice' This constant-current de; vice may be of anywell-known.construction, such as the 'well known: iron wire "ballast lamp. Coils land 3 "are so connected that tlieirma'gnetonrotive forces oppose each other,th'e ampere'turn's ofathe coil 3 at nor mal voltage on'circuit l being greater than the ampere'current ofcoi'l' Vith this are rangem'ent anincreasod' voltage oncircuit 1 will .in'crease the current through coil 2, and therefore its 'ampere turns, but due to the welhlrhown action of constant current device l whichhas a high temperature coeflicient of resistance, the increase in. voltage" on cirs cuit 1 wi-ll all be absorbedby an increase in voltage drop-across resistance 4, so that. the ampere-turns ofcoil 3w1ll remain practically constant throughout a considerable range ofvoltage change on circuit '1. The

result willbe' that, as the magnetomotive forces of the coils are opposite, an. increase in voltage will result in a net decrease in the total-ampere turns of both "coils. Therefore the armature of sucha magnet which is conelements" 'tive than an ordinary magnet having coils arranged as shown in Fig. 1 will cause a decrease in operating force with increase in v ltage, this arrange ment has another advantage in that the effective number of ampere turnsof the magnet, and hence the force produced by the magnet varies at a greater rate than the-voltage applied to the coil.

able for producing a force 011 the armature For exmple, if at normal voltage the number of ampere turns of the III is 100. It now the exciting voltage increase by 1%, the number of ampere-turns of the variable current coil increases to 900, while the effective number of ampere turns of the entire system falls from to 91. Therefore, a change of the net ampere-turns of the two coils of 9% corresponds to a change of voltage'of 1%.

This corresponds to a variation of the attractive force of the magnet of about 20%. It will thus be seen that a reg ulator employing an operating magnet arranged as in Fig. 1, will be much more sensiregulator whose operating magnet has but a single coil.

In the modificationshown in Fig. 2, the same effect, but to a greater degree, is obtained. In this figure variable current coil 2 is connected across the ballast resistor 4. instead of directly across the circuit 1, constant current coil 3 being connected in series with. the ballast resistor 4.

If rapid movement of the armature of the operating magnet, caused by a great variation'in the attractive force of the magnet with slight voltage variations i s not desirable. its motion can be damped, by arranging shin't-circuited turns on the core of the operting magnet or on the armature.

In order to obtain the simplest possible mechanical construction of the regulator, it is desirable that the movable element of the operating. magnet press without intermediate members as directly as possible on the carbon pile This is made possible, according to another feature of the invention, by giving the magnet the same characteristics as those for the carbon pile. This is obtained as follows:

In Fig. l, 5 represents a carbon pile. L minimum represents the length oi. this pile when fully compressed. and L maximum represents the uncompressed length of this pile. P represents the compressing pressure, and

(1- represents the diflerence between the acin d are proportional to changes in the resistance of the pile, the curve illustrated in Fig.

3 is also illustrative of the pressure-resistance characteristic of the carbon pile. r p

In order to obtain best results with the movable element of theoper'ating magnet connected directly to press upon the carbon pile, it is necessarythat the operating magnet have'a characteristic which is similar to the characteristic of the carbon pile illustrated inFig. 3. An operatingmagnet having'this characteristic is illustrated-in Figs. 5 and 6, where 6 is the stationary core upon which the operatingcoils are wound, 7 is the armature which is pivotally mounted at 8, and 9 are .small non-magnetic pieces set in the poles of the stationary element 6 for preventing freezing of the armature to the core. P represents the force by which the armature is attracted to'thecore 6, while d represents the displacement of the armaturefrom the poles of the core 6. The operatingcharacteristics of such a magnet are illustrated in Fig. 7

with P theattractive force as ordinates and d the displacement of the armature as abseissae. As will be seen theshape of this-curve is very similiar to the operating characteristics of the carbon pile illustrated in Fig. 3. The fact that the lower part of this curve does not intersect the horizontal axis, but is asymptotic to it, is immaterial'from a practical standpoint. The special constructionof the operating magnetillustrated in Figs. 5

and 6,which gives this operating characteristic, resides in the fact that the length of the air gap is small in comparison with'its active cross-section. Y a

As any given carbon pile is only capable of carrying safely a certain maximum current, there is illustrated in'Fig. 8 an arrangement whereby this maximum current may be doubledfor any'pile. As shown, the pile is divided into three sections, 10,11 and 12, the middle section being half the total length of the pile, while the end sections 10 and 12 are respectively one-fourth the total'length of the pile. Conducting elements 13' and 14 serve to separate the sections of 'the pile, while conductingelements 15 and 16 are mounted at the ends of the pile. Conducting sections 15 and 16 are connected by con-- ductor 17, while intermediate conducting sections 13 and 14 are connected to conductors 1.8 and 19, which may be connected in any suitable regulating'circuit. It will be seen from this arrangement that the current through the pile has two paths, one being through. themiddle section 11 and thc other being through end sections 10 and 12in series. In thls manner the currentcarrying capacity Fig. 3 illustrates graphically Although the invention has only been shown and descr-ibedin connection with a carbon pile regulator it will be readily apparent to those skilled in the art that the invention is not so limited and that it is suitable for use with any compressible resistance medium-having "characteristics similar to' those of a carbon pile. I .7 j

Figs. 9 and'10 illustrate the completed regulator embodying the above-described features of the invention. In these figures 24 is a baseupon which abracket 25 is fastened by any suitable means. Supported bythis bracket is the carbon pile 5. This bracket also supports through a pivotal connection 8, the armature 7 of the operating magnet. A counterbalance 20 is provided for the arma-'- ture in order to relieve the pressure on the pile, due to the weight of the armature, when the operating magnet is fully energized. As shown, the'carbon pile is hollow and has passing through it arod 21, which connects at its lower end to the armature 7, and at its upper end to the upper end of thecarbon pile 5 by means of a nut 22, whereby an adjustment of the setting may be secured. Bracket 25 alsocarries an adjustable stop 23. A suitable supporting bracket 26'serves to fasten vage regulator in which themovable element of the operating magnet is connected directly to the carbon'pile, the pressure-displacement characteristic of the operating magnet being similar in shape to the pressuredisplacement or pressure-resistance character'istic of the carbon pile, while at the same time the force produced by the" operating magnet decreases with increases in the magnitude of the regulated qu'antity,so that with such increases the resistance of the carbon pile will also increase. V IVhile there have been shown and described particular embodiments of the invention. it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention} and it is therefore intended in the appended claims to cover all such. changes and modifications as fall within thetrue spirit and scope of the invention. IVhat I claim asnew and desire to secure by Letters-Patent of the UnitedStates is 1'. An electrical regulator having an oper-' ating magnet for a compressible pile including two differentially related coils, one of which normally produces a greater number of ampere-turns than the other, and a con- 1 stant current device associated with the coil normally producingtlie greatest number of ampere-turns.

2. In a regulating system for the voltage of an electric circuit, a compressible pile regu- 1 iii later having'an operating,niagnet comprising-a pair of differentially acting coilsconnected to be responsive to the voltage of said circuit, a constant current device associated with one of said coils for maintaining constant current in said coil regardless of the voltage of said circuit, said coil producing a greater number of ampere turns than the other atnormal voltage, whereby the rate of change of net ampere-turns in said magnet in responseto changes in the voltage of said circuit, is greater than the rate of change of voltage of said circuit.

3. An operating magnet for an electrical regulator having two parallel connected differentially acting coils, and a constant current device in series with one of said coils.

4; An operating magnet for anelectrical regulator having two parallel connected differentially acting coils, one of which is connectedin series With a constant current device, said coil being adapted to normally produce a greater number of ampere turns than the other.

5. An operating magnet for a compressible pile electrical regulator having two series connected differentially acting coils, one of which is in parallel with a constant-current device.

(5. An operating magnet for a compressible pile electrical regulator having two series connected differentially acting coils, one of which is in parallel with a constant current device, and the other of which normally produces the greater number of ampere turns.

7. In combination, an electric circuit having a normal voltage, an operating magnet for a: carbon pile voltage regulator including a pair of coils connected across said circuit, and a constant current device associated with oneof said coils in a manner to maintain the currenttherein substantially constant during voltage variations on said circuit, said coils being dill'erentially related with respect to a. connnon magnetic circuit, the constant current coil being adapted to produce the great est number of ampere turns at normal voltage.

8. In combination, an electric circuit havinga normal voltage, an operating magnet for carbon pile voltage regulator including a pair of coils connected in parallel across said circuit, and a constant current device'associated with one of said coils in a manner to maintain the current therein substantially constant during voltage variations on said circuit, said coils being differentially related with respect to a common magnetic circuit, the constant current coil being adapted to produce the greatest number of ampere turns at normal voltage.

9. In combination, an electric circuit having a normal voltage, an operating magnet for a carbon pile voltage regulator including a pair ofcoils connected in series across said circuit, and a constant current device associated with oneot said coils in :a manner to maintain the current therein substantially constant during voltage variations on said circuit, said coils being differentially related with respect to a common magnetic circuit, the constantcurrent coil being adapted to produce the greatest number of ampere turns at normal voltage.

10. An electrical regulator comprising a compressible resistance element having a pressure-resistance characteristic substantially hyperbolic in shape, and a compressing electromagnet for said resistance element, said electromagnet having a core and cooperating armature, the air gap between which is short with respect to its cross-section whereby the "force-displacement characteristic of said electromagnet is substantially the same as the pressure-resistanee characteristic of said resistance element.

11.. In combination, a carbon pile, an electron'iagnet, a core for said electroniagnet, said core having a pole, a movably mounted armature adjacent to said pole, the air gap between said pole and said armature being short in comparisonwith its cross-section. and means connecting said armature to said carbon pile in such a manner that the movements of said armature toward said pole result in a directly proportional motion of one end of said pile toward i other end.

12. An electrical regulator, having in combination, a resistance element whose electrical resistance varies inversely with the compressing pressure applied to it, an electromagnetic device having a core and an armature, said device producing an attractive force between its core and armature which varies inversely with its energization, and means for applying this force directly to said resistance element as a compressing pressure.

An electrical. regulator comprising, a carbon pile resistance, an electromagnet having a magnetic core and a movable magnetic armature, the electromagnetic attraction be tween said core and armature varying with the distance between them in substantially the same way that the force required to co1npress the carbon pile varies with its degree of compression, means directly connecting said armature to said core so that movements of said armature toward its cooperating core fause a directly proportional compression of said pile, and energizing means for said electroniagnet which decreases its net ampere turns witlrincreases in the voltage applied to it.

1.4. An electrical. regulator having in combination a carbon pile, a support for one end of said pile, an armature of magnetic material, a core of magnetic material adapted to attract said armature when said core is energized, connecting means between said armature and the unsupported end of said carbon pile for causing the attractive force on said armature to be applied directly to compressing said pile, a pair of coils wound on said core, said coils being difierentially related, one of said coils normally producing a, greater number of ampere turns than the 

